I just bought this pattern five days ago and have already sewn all three items in a 3T. I love everything about them ... except the fit on my tall, skinny 2.5-year-old. I wasn't confident messing with the pattern before sewing it once through, since I don't have a lot of experience. But the pants and skirt are falling off her. Her waist measurement is less than 19" - so the 6-12 month size. But she is tall and needs the length of the 3T. I want to sew another skirt and pair of pants. Is it as simple as using the 6-12 month pattern but adding extra length to correspond with the 3T pattern in the rise and inseams? Anyone done this? Thanks!